Question

electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 4000-angstrom .what is the threshold frequency

Answer 1

Answer:

Since, K.E is zero, the energy of radiation is equal to the work function of the metal. Also, the threshold frequency is equal to the frequency of radiation.

The threshold frequency is

ν

o

=ν=

λ

c

=

6800×10

−10

3.0×10

8

m/s

m

=4.41×10

14

/s.

The work function is

hν

0

=6.626×10

−34

×4.41×10

14

=2.92×10

−19

J.

Explanation:

hope it helps you.......